LieutenantMary Sue was a half-Vulcan/half-HumanStarfleet officer who served on the USS Enterprise when she was only "fifteen and a half years old." James T. Kirk found her exceptionally attractive (for a minor) and Spock admired her mind. She joined Kirk, Spock, McCoy and Scotty on a mission to Rigel XXXVII, where they were attacked by green androids and subsequently imprisoned. Mary Sue picked the lock with her hairpin and the crew escaped back to the ship.

However, all the men that had beamed down to the planet were stricken with "jumping cold robbies." As the least affected member of the landing party, Mary Sue took command of Enterprise and ran it so well that she was honored with the Nobel Peace Prize, the Vulcan Order of Gallantry and the Tralfamadorian Order of Good Guyhood.

However, the disease eventually reached her and she died. Her birthday became a "national holiday" aboard Enterprise. (A Trekkie's Tale)